The present invention relates to numerically controlled electric discharge machines, and more particularly to a numerically controlled electric discharge machining system in which, in a machining operation instructed according to a numerical control program, a machining time can be controlled.
FIG. 1 is a block diagram showing the arrangement of a control circuit for a conventional numerically controlled electric discharge machine system (hereinafter referred to as "an NC EDM system", when applicable).
In FIG. 1, reference character 1A designates a microprocessor for processing data which are applied thereto from a paper tape input-output unit 3, or from a keyboard 6, or through an input-output unit 7 from a flexible disc 8 (hereinafter referred to as "a CPU 1A", when applicable); 2, a memory unit for storing data, the memory unit 2 comprising a read-only memory section (hereinafter referred to as "a ROM section", when applicable) in which the control program of the CPU 1A is stored, and a memory section for writing and reading data (hereinafter referred to as "a RAM section", when applicable); 3, the aforementioned paper tape input-out unit for punching a paper tape or reading data out of the paper tape thus punched; 4, a display unit for displaying data on it (hereinafter referred to as "a CRT 4", when applicable); 5A, a time integrating meter for detecting a machining time etc.; 6, the aforementioned keyboard for inputting data and commands; 8, the aforementioned flexible disc for transmitting and receiving data through the input-output unit 7; 9, a data bus for transmitting data; and 10, the NC electric discharge machine.
The operation of the control circuit shown in FIG. 1 will be described. A numerical control program (hereinafter referred to as "an NC program", when applicable) ,is applied from the paper tape input-output unit 3, or from the keyboard, or through the input-output unit 7 from the flexible disk 8 to the CPU 1A, where it is analyzed into numerical control data for driving the NC electric discharge machine 10. The NC data thus obtained is transmitted through the data bus 9 to the NC electric discharge machine 10. When a time reading command is issued according to the NC program, the CPU IA reads the present integrated time, and stores it in the RAM section of the memory unit 2. Owing to this time reading function, a necessary machining time can be calculated by executing a time reading command immediately before the start of a machining operation and immediately after the end of the machining operation.
In the conventional NC EDM system thus organized, a machining time etc. can be calculated automatically, but a machining procedure including the starting of the NC electric discharge machine etc. has not been automated yet. Accordingly, operations such as the starting of the NC electric discharge machine, the injecting of a machining solution, and the starting of a machining operation have to be manually carried out.